Locking means for adjustable back chairs



NOV. 16, 1948. l T H VAN BUREN 2,453,879

LOCKING MEANS FOR ADJUSTABLE BACK CHAIRS Filed Nov. 9, 1946 Patented Nov. 16, 1948 LOCKING MEANS FOR ADJUSTABLE BCK CHAIRS Tracy H. Van Buren, Sturgis, Mich.

Application November 9, 1946, Serial No. 708,893

9 Claims.

This invention relates to improvements in Vadjustable chairs. f

The main objects of this invention are:

First, to provide an adjustable chair having a wide range oi adjustment and which may be quickly and easily adjusted to the` particular requirements or comfort of the user. p

Second, to provide in a chair means for adjustably supporting the back which is very secure and does not dependA on screws or clamping adjusting means. i i

Third, to provide a back supporting and adjusting means for chairs embodying coacting clutch members which maybe easily engaged and disengaged and one in which the strains and stresses thereon are well distributed.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is dened and pointed out in the claims.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. l is a side elevation of a chair embodying my invention.

Fig. 2 is'an enlarged fragmentary view mainly in section on a line corresponding to. line 2-2 of Fig. 4.

Fig. 3 is an enlarged fragmentary view mainly in section. on line 3-3 of Fig. 2.

Fig. 4 is a view mainly in transverse section on line @-4 of Figs. 2 and 3.

Fig. 5 is an. elevational view of one of the cam elements.

Fig. 6 is a fragmentary elevational view of the other cam element. i

The embodiment of the invention illustrated is an oice chair comprising a pedestal I, a seat i12-provided with the vertically adjustable spindle 3. The back of the structure ilustrated comprises a supporting bar 4 carrying the pad-like back member 5 which is tiltably mounted on the pvot 6. form no part of my present invention and are therefore not illustrated.

The back supporting arm l is disposed below the seat and projects rearwardly from the spindle 3. This arm is provided with a segmental curved serrated jaw 8 at its rear end. The backl bar 4 is engaged in the socket 9 of the back supporting bracket IB. This back supporting bracket is provided with a curved segmental serrated jaw II at its forward end. i The serrations or the teeth of these jaws are laterally inclined in the same direction.

The details however of this mounting The supporting link designated generally by the numeral I2 comprises a, pair of link members I3 and I4 which are. conformed to provide `a. central chamber` I5. The link members are secured together and pivotally. connected to the arm 1 and bracket l0 by rivets IB. These combination rivetsv and pivots are centered relative tothe jaws 8 and II. f

The intermediate or adjusting clutch 'member Il is provided with segmental concaved serrated or toothed jaws I8 at its ends, the serrations or teeth .being inclined laterally and oppositely to the serrations or teeth of .the jaws 8 and I I. VThe adjusting clutch member I1 is supported for lateral sliding adjustment by means of the Ways I9 provided on the link I2 for the purpose.

The adjusting clutch member I1 is adjusted into and out ofengagement by means of the spindle 2U rotatably mounted in the supporting link I2 and provided with a hand piece 2l at one end, the hand piece being secured thereto, by the pin 22 i v f The spindleisshouldered at 23 to engage one side of the clutch member` I1 and is provided with a pin 24 engaging the other side, this connection permitting vrotative movement of. the spindle within the adjusting clutch member. The spindle is provided with means for moving it axially when it is rotated. In the embodiment illustrated this comprises the cam element 25 which is formed at the bottom of the recess 26 in the link member I4 and a coacting cam element 21 formed on theinner face of the closure member 28 for the recess.

This closure member `2li has an annular groove 29 on its inner side receiving the annular flange 3l) on the link member I4 to which it is secured by the screws 3l. These cam elements in effect y provide a cam groove with which the pin 32 on the spindle coacts so that when the spindle is rotated an axial movement is imparted thereto and inasmuch as the adjusting clutch member is connected to the spindle for axial movement therewith the clutch jaws are moved into and out of engagement. i

When the parts are in engaged position they i are very securely locked in adjusted position and 1,796,949, issued March 17, 1931. The structure oi my invention, however, has many advantages not present in or incident to the structure of the said patent both from the manufacturing stand point, ease and security of adjustment and in the distribution or strain on the parts.

I have illustrated and described my invention as embodied kin an ottico chair. I have not attempted to illustratel or vdescribeother embodiments or adaptations as it is believed that this disclosure will enable those skilled in the art to embody or adapt my invention as may be' desired.

Having thus described my invention, what Iv claim as new and desire to secure by Letters Patent is:

1. In a chair, the combinati-on with aseat a back supporting bar, of a back supporting arm disposed below the seat and provided with a segmental serrated clutch jaw at its outer end, a supporting bracket for said back bar provided with a lsegmental" serrated clutch jaw at its' front end, the seri-ations of said jaws being transverselyy inclined in the' same direction, lra supporting link comprising a pair of opposed memm bers disposi-idV on opposite' sides of said arm and bracket, said link members being connected to each other and pivotally connected to said arm and' bracket by fastener members centered relative to the' said jaws, an adjusting clutch member having concaved segmental serrated jaws at theends thereof ccacting with the' clutch jaws of said arm and bracket, the serrations of said adjusting clutch member jaws being transversely inclined oppositely to the serrations' of said jaws of said varm and bracket, a spindle rotatably mounted' on said linkvbetween said arm and bracket jaws and provided with a band piece, said spindle rotatably engaging said` adjusting clutch member and having a 'shoulder engag-4 in'g one side thereof and a* pin engaging the other, kone of said link members being provided with outwardly facing recessv having a at the bottom thereof, and a closure' for said recess provided with a cam opposed to said first named' @am and coacting therewith to provide a l'cam groove', said spindle having a pin eng'ag ing said cam' groove whereby rotative movement of the spindle imparts axial movement thereto to engage and rc'iiseng'age said adjusting clutch member, one of said link members being pro vided with ways slide-bly supporting said adjustingclutclr member. i

2.. In a chair, the combination with a seat and a back support-ing bar; of a supporting arm disposed below the seat and provided with a segmental'serrated clutch jaw at its outer end,va supporting for said back' bar pro-- vided with a segmental serrated clutch jaw at its front end, a supporting linkcomprising a pai-r of 'opposed members disposed oil opposite sides of said arm and bracket, said' link members being connected to each other and pivotally connected to said arm and bracket by fastener members centered relative to the said jaws,- an adjusting clutch member having concave-d segmental jaws at the ends' thereof coactiiig with the clutch jaws of said arin and bracket, a spindle rotat- Bbly mounted on said link between said tiin and bracket jaws and provided with a hand piece, said spindle rotatably engaging said adjusting' cluth member and having a shoulder engaging one side thereof and a pir-'i engaging the other, one" of Sad link meh-ib i u lrs being provided with an outwardly facing i-ecess having a cam at the bottom thereof, and a closure for said recess provided with a cam opposed to said rst named cam and coacting therewith to provide a cam groove, said spindle having a pin engaging said cam groove whereby rotative movement of the spindle imparts axial movement thereto to engage and disengage said adjusting clutch member.

3". In a chair, the combination with a seat and a back supporting bar, of a back supporting arm disposed below the seat and provided with a seg- 'mental serrated clutch jaw at its outer end, a supporting bracketJ for said back bar provided with a segmental serrated clutch jaw at its front end, the serrations of said jaws being transversely inclined in the same direction, a supporting link comprising a pair of opposed members disposed on opposite sides of said arm and bracket, said link members being connected to each other and pivotally connected to said arm and bracket by fastener members centered relative to the said jaws, an adjusting clutch member slidab-ly mounted on said linkand having concaved sesmental serrated jaws at the ends thereof coacting with the clutch jaws of said arm and bracket, the serratiohs of saidy adjusting clutch member jaws being transversely inclined oppositeiy to the serrations of said jaws of said arm and bracket, and a spindle 'rotatably mounted on said link between said and bracket jaws, said link being provided with cam means with which said spindle coacts to impart axial movement to the spindle when the spindle is rotated, said spindle being operatively connected to the adjusting clutch member so that the adjusting clutch member is engaged and disengaged by a rotative movementof the spindle.

4.- In a chair, the combination with a seat; and

a back supporting bar, of a back supporting arm disposed below the seat and provided with a segmental serrated clutch jaw at its outer end, a supporting bracket for said back bar provided with a segmental serrated clutch jaw at its front eri-d, a supporting comprising a pair oi' opposed members disposed. on opposite sides of said arm and bracket, said link members being connected to each other and pivotally connected to said arm and bracket by fastener members 'centered relative tothe said jaws, an adjusting clutch member slidably mounted on said link and `having serrated jaws at the ends thereof coacting with the clutch jaws of said arm and bracket, and a spindle rotatably mounted on said link between said arm and bracket jaws, said link being provided' with cam means with which said spindle coacts to impart axial movement to the spindle when the spindle is rotated, said spindle being operatively connected to ad justih'g clutch member so thatl the adjusting clutch member is engaged and disengaged by a rotative movement of the spindle.

5. In a chair, the combination with a seat and back, of. a back supporting arm disposed below the seat and provided with a segmental serrated clutch jaw, a back supportingv bracket provided with a segmental serrated clutch jaw, the serrations of said jaws being transversely inclined in the same direction, a supporting link pivotally connected to' said arm and bracket, pivots being centered relative to the jaws thereof, a coactin'g clutch adjusting member provided with serrated clutch jaws operatively associated with the 'clutch jaws of said arm and bracket and transversely inclined oppositely to the jaws of said arm and bracket, means for engaging and disengaging said coupling clutch member comprising a spindle rotatably mounted on said link and having lcam means associated therewith whereby the spindle is moved axially by a rotative movement thereof, said adjusting clutch member being connected to said spindle for movement axially therewith.

6. In a chair, the combination with a seat and 4 a back supporting bar, of a back supporting arm l disposed below the seat and provided with a segmental serrated clutch jaw at its outer end, a supporting bracket for said back bar provided with a segmental serrated clutch jaw at its front end, the serrations of said jaws being transversely inclined in the same direction, a supporting link comprising a pair of opposed members disposed on opposite sides of said arm and bracket, said link members being `connected to each other and pivotally connected to said arm and bracket by fastener members centered relative to the said jaws, an intermediate clutch member slidably mounted on said link and having concaved segmental jaws at the ends thereof coacting with the clutch jaws of said arm and bracket, the serrations of said adjusting clutch member jaws being transversely inclined oppositely to the serrations of said jaws of said arm and bracket, and means for laterally adjusting said intermediate clutch member.

7. In a chair, the combination with a seat and a back supporting bar, of a back supporting arm disposed below the seat and provided with a segmental serrated clutch jaw at its outer end, a supporting bracket for said back bar provided with a segmental serrated clutch jaw at its front end, a supporting link comprising a pair of opposed members disposed on opposite sides of said arm and bracket, said link members being connected to each other and pivotally connected to said arm and bracket by fastener members centered relative to the said jaws, an intermediate clutch member slidably mounted on said link and having serrated jaws at the ends thereof coacting with the clutch jaws of said arm and bracket, and means 4rfor laterally adjusting said intermediate clutch member.

8. In a chair, the combination with a seat and back, of a rearwardly projecting back supporting arm provided with a curved toothed clutch jaw, a back supporting bracket provided with a curved 5 toothed clutch jaw, a supporting link pivotally connected to said arm and bracket with the pivots centered relative to said jaws, a coacting `adjusting clutch memberprovided with curved toothed clutch jaws operatively associated with 10 the clutch jaws of said arm and bracket to be engaged with and disengaged therefrom by a lateral movement thereof, the teeth of the coacting jaws being laterally inclined to facilitate engagement thereof, and means for shifting said adjusting clutch member into and out of engaging position comprising a spindle rotatably mounted on said link and having cam means associated therewith whereby the spindle is moved axially by a rotative movement, said adjusting member being connected to said spindle for movement axially therewith.

9. In a chair, the combination with a seati and back, of a rearwardly projecting back supporting arm provided with a curved toothed clutch jaw, l

a back supporting bracket provided with a curved toothed clutch jaw, a supporting linkpivotally connected to said arm and bracket withthe pivots centered relative to said jaws, a coacti'ng adjusting clutch member provided with curved toothed clutch jaws operatively associated with the clutch jaws of said arm and bracket to beengaged with and disengaged therefrom by .a lateral movement thereof, and means for shifting said adjusting clutch member into and out of engaging position.

TRACY H. VAN BUREN.

REFERENCES CITED The following referencesffare of record in the o file of this patent:

UNITED sTATs PATENTS' Number Name!C Date 338,534 Livingstone` Mar. 23, 1886 1,796,949

Huntley Mar. 17, 1931 

